scholarly journals Expression and Function of the Endocannabinoid System in the Retina and the Visual Brain

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Jean-François Bouchard ◽  
Christian Casanova ◽  
Bruno Cécyre ◽  
William John Redmond
Keyword(s):  
Visual Processing ◽  
Metabolic Regulation ◽  
Cannabinoid Receptors ◽  
Endocannabinoid System ◽  
G Protein Coupled Receptors ◽  
Retinal Diseases ◽  
Pain Anxiety ◽  
Pharmacological Targets ◽  
And Function ◽  
G Protein Coupled

Endocannabinoids are important retrograde modulators of synaptic transmission throughout the nervous system. Cannabinoid receptors are seven transmembrane G-protein coupled receptors favoringGi/oprotein. They are known to play an important role in various processes, including metabolic regulation, craving, pain, anxiety, and immune function. In the last decade, there has been a growing interest for endocannabinoids in the retina and their role in visual processing. The purpose of this review is to characterize the expression and physiological functions of the endocannabinoid system in the visual system, from the retina to the primary visual cortex, with a main interest regarding the retina, which is the best-described area in this system so far. It will show that the endocannabinoid system is widely present in the retina, mostly in the through pathway where it can modulate neurotransmitter release and ion channel activity, although some evidence also indicates possible mechanisms via amacrine, horizontal, and Müller cells. The presence of multiple endocannabinoid ligands, synthesizing and catabolizing enzymes, and receptors highlights various pharmacological targets for novel therapeutic application to retinal diseases.

scholarly journals Potential metabolic and behavioural roles of the putative endocannabinoid receptors GPR18, GPR55 and GPR119 in feeding

2019 ◽  
Vol 17 (10) ◽  
pp. 947-960 ◽  
Author(s):  
Ricardo E. Ramírez-Orozco ◽  
Ricardo García-Ruiz ◽  
Paula Morales ◽  
Carlos M. Villalón ◽  
J. Rafael Villafán-Bernal ◽  
...  
Keyword(s):  
Cannabinoid Receptors ◽  
Potential Role ◽  
Therapeutic Potential ◽  
Eating Behaviour ◽  
Endocannabinoid System ◽  
G Protein Coupled Receptors ◽  
Know How ◽  
Feeding Control ◽  
G Protein Coupled

: Endocannabinoids are ancient biomolecules involved in several cellular (e.g., metabolism) and physiological (e.g., eating behaviour) functions. Indeed, eating behaviour alterations in marijuana users have led to investigate the orexigenic/anorexigenic effects of cannabinoids in animal/ human models. This increasing body of research suggests that the endocannabinoid system plays an important role in feeding control. Accordingly, within the endocannabinoid system, cannabinoid receptors, enzymes and genes represent potential therapeutic targets for dealing with multiple metabolic and behavioural dysfunctions (e.g., obesity, anorexia, etc.). Paradoxically, our understanding on the endocannabinoid system as a cellular mediator is yet limited. For example: (i) only two cannabinoid receptors have been classified, but they are not enough to explain the pharmacological profile of several experimental effects induced by cannabinoids; and (ii) several orphan G protein-coupled receptors (GPCRs) interact with cannabinoids and we do not know how to classify them (e.g., GPR18, GPR55 and GPR119; amongst others). : On this basis, the present review attempts to summarize the lines of evidence supporting the potential role of GPR18, GPR55 and GPR119 in metabolism and feeding control that may explain some of the divergent effects and puzzling data related to cannabinoid research. Moreover, their therapeutic potential in feeding behaviour alterations will be considered.

Roles of Endocannabinoids and Endocannabinoid-like Molecules in Energy Homeostasis and Metabolic Regulation: A Nutritional Perspective

2021 ◽  
Vol 41 (1) ◽  
Author(s):  
S.M. Khaledur Rahman ◽  
Toru Uyama ◽  
Zahir Hussain ◽  
Natsuo Ueda
Keyword(s):  
Arachidonic Acid ◽  
Metabolic Regulation ◽  
Energy Homeostasis ◽  
Cannabinoid Receptors ◽  
Biological Activities ◽  
Endocannabinoid System ◽  
Annual Review ◽  
Publication Date ◽  
Treatment And Prevention ◽  
G Protein Coupled

The endocannabinoid system is involved in signal transduction in mammals. It comprises principally G protein-coupled cannabinoid receptors and their endogenous agonists, called endocannabinoids, as well as the enzymes and transporters responsible for the metabolism of endocannabinoids. Two arachidonic acid–containing lipid molecules, arachidonoylethanolamide (anandamide) and 2-arachidonoylglycerol, function as endocannabinoids. N-acylethanolamines and monoacylglycerols, in which the arachidonic acid chain is replaced with a saturated or monounsaturated fatty acid, are not directly involved in the endocannabinoid system but exhibit agonistic activities for other receptors. These endocannabinoid-like molecules include palmitoylethanolamide, oleoylethanolamide (OEA), and 2-oleoylglycerol. Endocannabinoids stimulate feeding behavior and the anabolism of lipids and glucose, while OEA suppresses appetite. Both central and peripheral systems are included in these nutritional and metabolic contexts. Therefore, they have potential in the treatment and prevention of obesity. We outline the structure, metabolism, and biological activities of endocannabinoids and related molecules, and focus on their involvement in energy homeostasis and metabolic regulation. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Positron Emission Tomography in the Inflamed Cerebellum: Addressing Novel Targets among G Protein-Coupled Receptors and Immune Receptors

Pharmaceutics ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 925
Author(s):  
Margit Pissarek
Keyword(s):  
G Protein ◽  
Cannabinoid Receptors ◽  
G Protein Coupled Receptors ◽  
Translocator Protein ◽  
Brain Diseases ◽  
Present Contribution ◽  
Binding Behavior ◽  
Positron Emission ◽  
Inflammatory Processes ◽  
G Protein Coupled

Inflammatory processes preceding clinical manifestation of brain diseases are moving increasingly into the focus of positron emission tomographic (PET) investigations. A key role in inflammation and as a target of PET imaging efforts is attributed to microglia. Cerebellar microglia, with a predominant ameboid and activated subtype, is of special interest also regarding improved and changing knowledge on functional involvement of the cerebellum in mental activities in addition to its regulatory role in motor function. The present contribution considers small molecule ligands as potential PET tools for the visualization of several receptors recognized to be overexpressed in microglia and which can potentially serve as indicators of inflammatory processes in the cerebellum. The sphingosine 1 phosphate receptor 1 (S1P1), neuropeptide Y receptor 2 (NPY2) and purinoceptor Y12 (P2Y12) cannabinoid receptors and the chemokine receptor CX3CR1 as G-protein-coupled receptors and the ionotropic purinoceptor P2X7 provide structures with rather classical binding behavior, while the immune receptor for advanced glycation end products (RAGE) and the triggering receptor expressed on myeloid cells 2 (TREM2) might depend for instance on further accessory proteins. Improvement in differentiation between microglial functional subtypes in comparison to the presently used 18 kDa translocator protein ligands as well as of the knowledge on the role of polymorphisms are special challenges in such developments.

The Molecular targets of Cannabinoids in the treatment of Cancer and Inflammation

2021 ◽  
Vol 27 ◽  
Author(s):  
Alenabi Aylar ◽  
Malekinejad Hassan
Keyword(s):  
Cannabinoid Receptors ◽  
Inflammatory Diseases ◽  
Biological Effects ◽  
Synthetic Cannabinoids ◽  
Endocannabinoid System ◽  
Anticancer Effects ◽  
Anti Cancer ◽  
Culture Models ◽  
Cancer And Inflammation ◽  
G Protein Coupled

Objective: In this review we discuss the emerging evidence for the effectiveness of cannabinoids in the treatment of cancer and inflammation. The remarkable effects complete the traditional evidence for their successful application in the treatment of pain and cancer-related side effects. Methods: we searched Pub Med (132 articles) and Google scholar (9 articles) databases and gathered the clinical (4 articles), preclinical (28 articles) studies, reports on cell culture models (30 articles) and other original and review articles (78 articles) related to inflammation, cancer and cannabinoids. Results: Cannabinoids are described in three different forms, comprising endo- phyto- and synthetic compounds that exert biological effects. The molecular and cellular pathways of endogenous cannabinoids in the maintenance of homeostasis are well documented. In addition to classical cannabinoid receptors type 1 and 2, Vanilloid receptors and G protein-coupled receptor 55 were identified as common receptors. Subsequently, the effectiveness of phyto- and synthetic cannabinoids mediated by cannabinoid receptors has been demonstrated in the treatment of inflammatory diseases including neurodegenerative diseases as well as gastrointestinal and respiratory inflammations. Another accepted property of cannabinoids is their anti-cancer effects. Cannabinoids were found to be effective in the treatment of lung, colorectal, prostate, breast, pancreas and hepatic cancers. The anticancer effects of cannabinoids were characterized by their anti-proliferative property, inhibition of cancer cells migration, suppression of vascularization and induction of apoptosis. Conclusion: The current review provides and overview the role of endocannabinoid system in the mediation of physiological functions, the type and expression of cannabinoids receptors under physiological and pathological conditions. In additions, the molecular pathways involved in the effects of cannabinoids and the effectiveness of cannabinoids in the treatment of inflammations and cancers are highlighted.

scholarly journals Dopamine D3 Receptor Heteromerization: Implications for Neuroplasticity and Neuroprotection

Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1016 ◽  
Author(s):  
Federica Bono ◽  
Veronica Mutti ◽  
Chiara Fiorentini ◽  
Cristina Missale
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Neuronal Development ◽  
G Protein Coupled Receptors ◽  
D3 Receptor ◽  
Pharmacological Targets ◽  
Receptor Heteromers ◽  
Dopamine D3 ◽  
Functional Features ◽  
G Protein Coupled

The dopamine (DA) D3 receptor (D3R) plays a pivotal role in the control of several functions, including motor activity, rewarding and motivating behavior and several aspects of cognitive functions. Recently, it has been reported that the D3R is also involved in the regulation of neuronal development, in promoting structural plasticity and in triggering key intracellular events with neuroprotective potential. A new role for D3R-dependent neurotransmission has thus been proposed both in preserving DA neuron homeostasis in physiological conditions and in preventing pathological alterations that may lead to neurodegeneration. Interestingly, there is evidence that nicotinic acetylcholine receptors (nAChR) located on DA neurons also provide neurotrophic support to DA neurons, an effect requiring functional D3R and suggesting the existence of a positive cross-talk between these receptor systems. Increasing evidence suggests that, as with the majority of G protein-coupled receptors (GPCR), the D3R directly interacts with other receptors to form new receptor heteromers with unique functional and pharmacological properties. Among them, we recently identified a receptor heteromer containing the nAChR and the D3R as the molecular effector of nicotine-mediated neurotrophic effects. This review summarizes the functional and pharmacological characteristics of D3R, including the capability to form active heteromers as pharmacological targets for specific neurodegenerative disorders. In particular, the molecular and functional features of the D3R-nAChR heteromer will be especially discussed since it may represent a possible key etiologic effector for DA-related pathologies, such as Parkinson’s disease (PD), and a target for drug design.

The Mechanism and Function of Agonist-Induced Trafficking of G-protein Coupled Receptors

2000 ◽  
Vol 28 (3) ◽  
pp. A59-A59
Author(s):  
K. DeFea ◽  
O. Dery ◽  
F. Schmidlin ◽  
N.W. Bunnett
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
And Function ◽  
G Protein Coupled

Systems biochemistry approaches to vertebrate phototransduction: towards a molecular understanding of disease

2010 ◽  
Vol 38 (5) ◽  
pp. 1275-1280 ◽  
Author(s):  
Daniele Dell'Orco ◽  
Karl-Wilhelm Koch
Keyword(s):  
Electrical Response ◽  
Photoreceptor Cells ◽  
G Protein Coupled Receptors ◽  
Retinal Diseases ◽  
Rod Cells ◽  
Wide Range ◽  
Nucleotide Interactions ◽  
Light Stimuli ◽  
G Protein Coupled ◽  
Phototransduction Cascade

Phototransduction in vertebrates represents a paradigm of signalling pathways, in particular those mediated by G-protein-coupled receptors. The variety of protein–protein, protein–ion and protein–nucleotide interactions makes up an intricate network which is finely regulated by activating–deactivating molecules and chemical modifications. The holistic systems properties of the network allow for typical adaptation mechanisms, which ultimately result in fine adjustments of sensitivity and electrical response of the photoreceptor cells to the broad range of light stimuli. In the present article, we discuss a novel bottom-up strategy to study the phototransduction cascade in rod cells starting from the underlying biochemistry. The resulting network model can be simulated and the predicted dynamic behaviour directly compared with data from electrophysiological experiments performed on a wide range of illumination conditions. The advantage of applying procedures typical of systems theory to a well-studied signalling pathway is also discussed. Finally, the potential application to the study of the molecular basis of retinal diseases is highlighted through a practical example, namely the simulation of conditions related to Leber congenital amaurosis.

scholarly journals Methods used to study the oligomeric structure of G-protein-coupled receptors

2017 ◽  
Vol 37 (2) ◽  
Author(s):  
Hui Guo ◽  
Su An ◽  
Richard Ward ◽  
Yang Yang ◽  
Ying Liu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
G Protein ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
G Protein Coupled Receptors ◽  
Experimental Techniques ◽  
Distribution Analysis ◽  
Wide Range ◽  
And Function ◽  
G Protein Coupled

G-protein-coupled receptors (GPCRs), which constitute the largest family of cell surface receptors, were originally thought to function as monomers, but are now recognized as being able to act in a wide range of oligomeric states and indeed, it is known that the oligomerization state of a GPCR can modulate its pharmacology and function. A number of experimental techniques have been devised to study GPCR oligomerization including those based upon traditional biochemistry such as blue-native PAGE (BN-PAGE), co-immunoprecipitation (Co-IP) and protein-fragment complementation assays (PCAs), those based upon resonance energy transfer, FRET, time-resolved FRET (TR-FRET), FRET spectrometry and bioluminescence resonance energy transfer (BRET). Those based upon microscopy such as FRAP, total internal reflection fluorescence microscopy (TIRFM), spatial intensity distribution analysis (SpIDA) and various single molecule imaging techniques. Finally with the solution of a growing number of crystal structures, X-ray crystallography must be acknowledged as an important source of discovery in this field. A different, but in many ways complementary approach to the use of more traditional experimental techniques, are those involving computational methods that possess obvious merit in the study of the dynamics of oligomer formation and function. Here, we summarize the latest developments that have been made in the methods used to study GPCR oligomerization and give an overview of their application.

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